As an electromagnetic contactor having a contact point mechanism stored in an arc-extinguishing chamber of the electromagnetic contactor, there is proposed, for example, a sealed contact device that has a sealed container made of ceramic or other heat-resistance material and shaped into a box with one open surface (see Patent Document 1, for example). In the sealed contact device described in Patent Document 1, fixed terminals are brazed and airtightly bonded to two through-holes formed in a bottom part of the sealed container. A movable contact is disposed in the sealed container. The movable contact is provided with a movable contact point that contacts with and separates from fixed contact points formed at the fixed terminals. An open end part of the sealed container is connected to a first bonded member by a tubular metallic second bonded member, the first bonded member being shaped into a rectangle by means of a magnetic metallic material and has a bottomed tubular part seal-bonded thereto.
Patent Document 1: Japanese Patent Publication No. 3107288
Incidentally, in the conventional example described in Patent Document 1, the sealed container is formed into a box with one open surface by using ceramic or other heat-resistance material, and the fixed terminals are brazed to the sealed container. In this sealed container, tip ends of the fixed contact points protrude into the sealed container to fix the fixed terminals to a bottom plate part of the sealed container. The movable contact is disposed facing a lower side of the fixed contact points to be capable of contacting with and separating from the fixed contact points.
Therefore, when assembling the sealing container, no special assembly method is needed because the fixed terminals can simply be disposed fixedly in the sealed container. However, when a large current flows in a closed pole state where the movable contact contacts the fixed terminals, electromagnetic repulsive force acts in an open pole direction in which the movable contact separates from the fixed terminals, making the contact state between the fixed terminals and the movable contact unstable.
In order to solve this problem and stabilize the contact state between the fixed terminals and the movable contact, there is considered a way to generate the Lorentz force that acts against the electromagnetic repulsive force, by bending each fixed terminal into an L-shape or C-shape and disposing a coupling part, which is connected to a plate part in which a contact point part is disposed, in the vicinity of contact point parts of the fixed terminals and a contact point part of the movable contact.